Energy from renewable sources is up to 10 times cheaper than from non-renewable sources, but is not continuous.

There is thus a strong economic incentive to develop technologies for capturing this transiently source of energy and storing it, adding value by making it continuously available.

Note that there is a parallel incentive to develop technology for exploiting intermittent energy sources more effectively.

Hydrogen can be generated instantly from non-renewable sources and transmitted relatively short distances by pipeline, but storage and transport over longer distances is not so easy. However, there will be many situations where the total cost of generating the gas, storing and transporting it and generating continuous energy from it, is substantially less than non-renewable energy.

We do need to think about the role of carbon compounds, in the context of both fuels and climate change.

Elsewhere, I have suggested that the metal magnesium has potential to be used as a means of storing energy. It is abundant in nature, non-toxic, stable and easy to store and transport. Its energy density by weight is about the same as hydrocarbons and by volume half. The trouble is that it will need several decades to develop the necessary technology.

Ammonia and Li-ion batteries are also proposed systems for storing, transmitting and using energy and are compared. (Note I have used the term “Energy System” rather than “Economy”

Energy as a currency

Anything that is to serve as a currency has to have a universally recognised value and be spendable, stable, storable, and portable. At various times all sorts of things have been used as tokens of value: sharks teeth, gold, stamps, tulip bulbs, and floating point operations in the case of bitcoins.

Energy certainly has universally recognised value but as electricity can only be transferred by power lines, which are lossy and geographically limited, and can only be stored by transforming it into a different form, eg, chemical energy in batteries .

If it could be stored economically, surely energy would be the ultimate, most meaningful token of value.

The currency unit would be an amount of energy available as a continuous supply. A unit of 1GJ from non-renewable sources, coal, oil, gas, and uranium (and Thorium) would be about £100.

Fossil fuel has these properties and “tonnes of oil equivalent” (toe) is widely used as a unit of energy consumption.

Hydrogen looks good and the technology exists. Transport over longer distances and recovery is not very efficient. (Electrical energy can be obtained via a fuel cell or a thermal power station both with about 60% efficiency).

Magnesium would be good if the technology could be developed.

If energy can be stored in the form of Magnesium and Hydrogen. It looks very likely that a “green” unit based on Hydrogen and Magnesium and maybe Aluminium would be substantially lower than the non-renewable unit.

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